class Solution {
public:

    bool row[9][10];
    bool col[9][10];
    bool grid[3][3][10];
    bool isValidSudoku(vector<vector<char>>& board) {

        for (int i = 0; i < 9; i++)
        {
            for (int j = 0; j < 9; j++)
            {

                if (board[i][j] != '.')
                {
                    int num = board[i][j] - '0';
                    if (row[i][num] || col[j][num] || grid[i / 3][j / 3][num])
                        return false;
                    row[i][num] = col[j][num] = grid[i / 3][j / 3][num] = true;
                }

            }
        }

        return true;
    }
};